CN113728167B - Centrifugal compressor and supercharger - Google Patents

Abstract

The centrifugal compressor is provided with: an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body; an intake passage (130) which is disposed so as to face the impeller in the rotational direction; and a throttle mechanism having a throttle member (first throttle member (210)) provided in the intake passage (130), wherein the ratio calculated by dividing the distance (LL) between the outer peripheral end of the Leading Edge (LE) of the vane and the throttle member by the maximum protruding height (h _max) of the throttle member protruding from the inner wall surface of the intake passage (130) is 4 or less.

Description

Centrifugal compressor and supercharger

Technical Field

The present disclosure relates to centrifugal compressors and superchargers. The present application claims priority from japanese patent application No. 2019-086357, filed on 4/26 of 2019, and the contents thereof are incorporated herein.

Background

The prior art has provided centrifugal compressors in superchargers. For example, in the centrifugal compressor provided in the supercharger described in patent document 1, an intake passage is formed upstream of a compressor impeller. A throttle member is provided in the intake passage. The throttle member is provided in plurality in a circumferential direction of the compressor wheel. The throttle member is driven by the actuator and protrudes radially inward in the intake passage, thereby throttling the intake passage.

Prior art literature

Patent literature

Patent document 1 Japanese patent laid-open publication 2016-173051

Disclosure of Invention

Problems to be solved by the invention

The intake passage is throttled by the throttle member, so that the reduction in heat insulation efficiency at low flow rates is suppressed. There is a need for development of a technique for further suppressing a decrease in heat insulation efficiency when the intake passage is throttled in this manner.

The present disclosure aims to provide a centrifugal compressor and a supercharger, which can suppress reduction in heat insulation efficiency.

Means for solving the problems

In order to solve the above problems, a centrifugal compressor according to an aspect of the present disclosure includes: an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body; an intake passage facing the impeller in the rotation axis direction; and a throttle mechanism having a throttle member provided in the intake passage, wherein a ratio calculated by dividing a distance between an outer peripheral end of a leading edge of the vane and the throttle member by a maximum protruding height of the throttle member from an inner wall surface of the intake passage is 4 or less.

The throttle member may have an opposing surface that faces the outer peripheral end in the axial direction of the impeller, and the opposing surface may be provided between a position in the axial direction of the outer peripheral end and a position in the axial direction of the inner peripheral end of the leading edge.

In order to solve the above problems, a supercharger according to an aspect of the present disclosure includes the centrifugal compressor.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, a decrease in insulation efficiency can be suppressed.

Drawings

Fig. 1 is a schematic cross-sectional view of a supercharger.

Fig. 2is an extracted view of the broken line portion of fig. 1.

Fig. 3 is an exploded perspective view of the components constituting the link mechanism.

Fig. 4 is a cross-sectional view taken along line IV-IV of fig. 2.

Fig. 5 is a first diagram for explaining the operation of the link mechanism (throttle mechanism).

Fig. 6 is a second diagram for explaining the operation of the link mechanism.

Fig. 7 is a third diagram for explaining the operation of the link mechanism.

Fig. 8 is a drawing of the two-dot chain line portion of fig. 2.

Fig. 9 is a graph showing a relationship between a distance and an improvement rate of heat insulation efficiency.

Fig. 10 is a view for explaining the range of arrangement of the protruding portion of the first throttle member.

Fig. 11 is a graph showing the result of simulation of the flow of the peeled air based on the equation 1.

Detailed Description

An embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values and the like shown in the embodiments are merely examples for easy understanding, and the present disclosure is not limited thereto except for the case of specific description. In the present specification and the drawings, elements having substantially the same functions and structures are denoted by the same reference numerals, and overlapping description thereof is omitted. In addition, illustration of elements not directly related to the present disclosure is omitted.

Fig. 1 is a schematic cross-sectional view of a supercharger TC. The direction of arrow L shown in fig. 1 will be described as the left side of the supercharger TC. The direction of arrow R shown in fig. 1 will be described as the right side of the supercharger TC. As shown in fig. 1, the supercharger TC includes a supercharger main body 1. The supercharger main body 1 includes a bearing housing 2. The turbine housing 4 is coupled to the left side of the bearing housing 2 by a fastening bolt 3. The compressor housing 100 is coupled to the right side of the bearing housing 2 by a fastening bolt 5.

The bearing housing 2 has a housing hole 2a. The accommodation hole 2a penetrates the supercharger TC in the right-left direction. A bearing 6 is provided in the housing hole 2a. In fig. 1, a full-floating bearing is shown as an example of the bearing 6. However, the bearing 6 may be another radial bearing such as a half-floating bearing or a rolling bearing. The main shaft 7 is pivotally supported by a bearing 6 so as to be rotatable. A turbine wheel 8 is provided at the left end of the main shaft 7. The turbine wheel 8 is rotatably housed in the turbine housing 4. A compressor impeller 9 (impeller) is provided at the right end portion of the main shaft 7.

The compressor wheel 9 has a main body portion 9a. The outer peripheral surface 9b of the main body 9a faces one side in the rotation axis direction of the compressor impeller 9 (hereinafter simply referred to as rotation axis direction; the axial direction of the main shaft 7, and the left-right direction of the supercharger TC). The back surface 9c faces the other side in the rotation axis direction. On the outer peripheral surface 9b, a plurality of blades 9d are provided at a distance in the circumferential direction of the outer peripheral surface 9 b. The blades 9d protrude from the outer peripheral surface 9b in the radial direction. The compressor impeller 9 is rotatably housed in the compressor housing 100. The compressor housing 100 has a first housing member 110 and a second housing member 120. The first and second case members 110 and 120 will be described in detail later.

The compressor housing 100 has an intake port 10. The intake port 10 is provided on the right side of the supercharger TC. The intake port 10 is connected to an air cleaner not shown. The diffuser flow path 11 is formed in a state where the bearing housing 2 and the compressor housing 100 are coupled by the fastening bolts 5. The diffuser flow path 11 pressurizes air. The diffuser flow path 11 is formed annularly from the inside to the outside in the radial direction (hereinafter simply referred to as radial direction) of the main shaft 7 (compressor impeller 9). The diffuser flow path 11 communicates with the intake port 10 via the compressor impeller 9 on the inner side in the radial direction.

In addition, a compressor scroll passage 12 is formed in the compressor housing 100. The compressor scroll passage 12 is annular. The compressor scroll passage 12 is located radially outward of the compressor wheel 9. The compressor scroll passage 12 communicates with an intake port of an engine, not shown. The compressor scroll flow path 12 also communicates with the diffuser flow path 11. When the compressor impeller 9 rotates, air is sucked into the compressor housing 100 through the suction port 10. The sucked air is accelerated by centrifugal force while flowing between the plurality of blades 9d of the compressor wheel 9. The increased air is pressurized in the diffuser flow path 11 and the compressor scroll flow path 12. The boosted air flows out from an unillustrated outlet and is guided to an intake port of the engine.

Thus, the supercharger TC includes the centrifugal compressor C (compressor). The centrifugal compressor C is configured to include: a compressor housing 100, a compressor wheel 9, and a compressor scroll passage 12.

An exhaust port 13 is formed in the turbine housing 4. The exhaust port 13 is opened on the left side of the supercharger TC. The exhaust port 13 is connected to an exhaust gas purifying device, not shown. The turbine housing 4 is provided with a flow passage 14 and a turbine scroll flow passage 15. The turbine scroll passage 15 is located radially outward of the turbine wheel 8. The flow path 14 is located between the turbine wheel 8 and the turbine scroll flow path 15.

The turbine scroll passage 15 communicates with a gas inlet not shown. Exhaust gas discharged from an exhaust manifold of an engine not shown is guided to the gas inflow port. The turbine scroll passage 15 also communicates with the passage 14 described above. Exhaust gas introduced from the gas inlet into the turbine scroll passage 15 is guided to the exhaust port 13 through the passage 14 and the space between the wings of the turbine wheel 8. The exhaust gas introduced into the exhaust port 13 rotates the turbine wheel 8 during the circulation thereof.

The rotational force of the turbine wheel 8 is transmitted to the compressor wheel 9 via the main shaft 7. As described above, the air is boosted by the rotational force of the compressor impeller 9 and is guided to the intake port of the engine.

Fig. 2 is an extracted view of the broken line portion of fig. 1. In fig. 2, the compressor wheel 9, the compressor housing 100, and a throttle member described later are shown in an extracted state. As shown in fig. 2, the first shell member 110 of the compressor shell 100 is located on the right side (side away from the bearing shell 2) as viewed in fig. 2 than the second shell member 120.

The first housing member 110 has a substantially cylindrical shape. The first case member 110 has a small diameter portion 110a, a medium diameter portion 110b, and a large diameter portion 110c. The small diameter portion 110a is farthest from the bearing housing 2. The large diameter portion 110c is closest to the bearing housing 2. The intermediate diameter portion 110b is located between the small diameter portion 110a and the large diameter portion 110c. The small diameter portion 110a has a smaller outer diameter than the intermediate diameter portion 110 b. The intermediate diameter portion 110b has a smaller outer diameter than the large diameter portion 110c. However, the first case member 110 may not have the small diameter portion 110a, the medium diameter portion 110b, and the large diameter portion 110c. For example, the outer diameter may be substantially constant in the direction of the rotation axis.

A through hole 111 is formed in the first case member 110. The through hole 111 penetrates the first case member 110 in the rotation axis direction. The through hole 111 penetrates the small diameter portion 110a, the middle diameter portion 110b, and the large diameter portion 110c in the rotation axis direction. One end of the through hole 111 is the air inlet 10 described above.

The through hole 111 has a parallel portion 111a and a reduced diameter portion 111b. The parallel portion 111a is located closer to one end side of the through hole 111 than the reduced diameter portion 111b. One end of the parallel portion 111a is the suction port 10. The inner diameter of the parallel portion 111a is substantially constant in the axial direction. One end of the reduced diameter portion 111b is continuous with the parallel portion 111 a. The inner diameter of one end of the reduced diameter portion 111b is substantially equal to the inner diameter of the parallel portion 111 a. The inner diameter of the reduced diameter portion 111b becomes smaller as it moves away from the parallel portion 111a (as it approaches the second case member 120).

A cutout 112a is formed in the outer peripheral portion of the end surface 112 of the first case member 110 on the second case member 120 side. The cutout 112a is, for example, annular.

A receiving groove 112b is formed in the end surface 112 of the first case member 110. The receiving groove 112b is recessed toward the intake port 10 (the side away from the second case member 120) with respect to the end surface 112. The storage groove 112b is, for example, substantially annular in axial direction. In other words, the receiving groove 112b is recessed radially outward from the inner wall of the through hole 111.

A bearing hole 112d is formed in a wall surface 112c of the housing groove 112b on the suction port 10 side (on the small diameter portion 110a side, on the side away from the second case member 120). The bearing hole 112d extends from the wall surface 112c toward the intake port 10 in parallel with the rotation axis direction. The bearing holes 112d are provided two by two in the rotation direction of the compressor wheel 9 (hereinafter simply referred to as the rotation direction). The two bearing holes 112d are arranged at positions offset by 180 degrees in the rotational direction.

A through hole 121 is formed in the second case member 120. The through hole 121 penetrates the second case member 120 in the rotation axis direction. The inner diameter of the end portion of the through hole 121 on the first case member 110 side is substantially equal to the inner diameter of the end portion of the through hole 111 on the second case member 120 side. A shield portion 121a is formed on an inner wall of the through hole 121 in the second case member 120. The shroud 121a faces the compressor wheel 9 from the radially outer side. The inner diameter of the shield portion 121a increases as it moves away from the first case member 110. The end of the shroud 121a opposite to the first case member 110 communicates with the diffuser flow path 11.

An accommodating groove 122a is formed in the end surface 122 of the second case member 120 on the first case member 110 side. The receiving groove 122a is recessed toward the diffuser flow path 11 side (the side away from the first case member 110) with respect to the end surface 122. The accommodating groove 122a is, for example, substantially annular in axial direction. In other words, the receiving groove 122a is recessed radially outward from the inner wall of the through hole 121. The large diameter portion 110c is inserted into the accommodating groove 122a. The end surface 112 of the first case member 110 is in contact with a wall surface of the accommodating groove 122a on the diffuser flow path 11 side.

The suction passage 130 is formed by the through hole 111 of the first case member 110 and the through hole 121 of the second case member 120. The suction passage 130 communicates the suction port 10 with the diffuser flow path 11. The compressor impeller 9 is provided in the intake passage 130. The cross-sectional shape of the intake passage 130 (through holes 111 and 121) perpendicular to the rotation axis direction is, for example, a circular shape centered on the rotation axis of the compressor wheel 9. However, the cross-sectional shape of the suction passage 130 is not limited thereto. A seal, not shown, is disposed in the cutout 112a of the first case member 110. The flow rate of the air flowing through the gap between the first and second case members 110 and 120 can be suppressed by the seal. But the cutout portion 112a and the seal are not necessarily structured.

Fig. 3 is an exploded perspective view of the components constituting the link mechanism 200 (throttle mechanism). In fig. 3, only the first shell member 110 in the compressor shell 100 is shown. As shown in fig. 3, the link mechanism 200 has: the compressor housing 100, a first throttle member 210 (throttle member), a second throttle member 220 (throttle member), a coupling member 230, and a rod portion 240.

The first throttling part 210 has a curved portion 211. The curved portion 211 has a substantially semicircular arc shape. One end surface 211a and the other end surface 211b in the rotation direction of the curved portion 211 extend in parallel with the radial direction and the rotation axis direction. But the one end surface 211a and the other end surface 211b may also be inclined with respect to the radial direction and the rotation axis direction.

An arm 212 is provided on the side of one end surface 211a of the curved portion 211. The arm portion 212 extends radially outward from the outer peripheral surface 211c of the curved portion 211. In addition, the arm portion 212 extends in a direction inclined with respect to the radial direction (toward the second throttle member 220 side).

The second throttling part 220 has a curved portion 221. The curved portion 221 has a substantially semicircular arc shape. One end surface 221a and the other end surface 221b in the rotation direction of the curved portion 221 extend parallel to the radial direction and the rotation axis direction. But the one end surface 221a and the other end surface 221b may be inclined with respect to the radial direction and the rotation axis direction.

An arm 222 is provided on one end surface 221a side of the curved portion 221. The arm 222 extends radially outward from the outer peripheral surface 221c of the curved portion 221. In addition, the arm portion 222 extends in a direction inclined with respect to the radial direction (toward the first throttle member 210 side).

The curved portion 211 and the curved portion 221 face each other across the rotation center (intake passage 130) of the compressor wheel 9. One end surface 211a of the curved portion 211 and the other end surface 221b of the curved portion 221 face each other. The other end surface 211b of the curved portion 211 is opposed to the one end surface 221a of the curved portion 221.

The coupling member 230 is located closer to the intake port 10 than the first and second throttle members 210 and 220. The connecting member 230 has a substantially circular arc shape. Bearing holes 231, 232 are formed in the coupling member 230 at one end side and the other end side in the rotational direction. The bearing holes 231 and 232 are formed in the end surfaces 233 of the coupling member 230 on the sides of the first and second throttle members 210 and 220. The bearing holes 231, 232 extend in the rotation axis direction. Here, the bearing holes 231 and 232 are formed of non-penetrating holes. However, the bearing holes 231 and 232 may penetrate the coupling member 230 in the rotation axis direction.

A rod portion connecting portion 234 is provided between the bearing holes 231, 232 in the coupling member 230. The rod portion connecting portion 234 is provided on an end surface 235 of the connecting member 230 on the opposite side of the first and second throttle members 210 and 220. The rod portion connecting portion 234 protrudes from the end surface 235 in the rotation axis direction. The stem connection 234 is, for example, generally cylindrical in shape.

The stem 240 has a generally cylindrical shape. A flat portion 241 is formed at one end of the lever portion 240. The planar portion 241 extends substantially along a plane direction perpendicular to the rotation axis direction. The flat portion 241 is provided with a bearing hole 242. The bearing hole 242 extends along the rotation axis direction. The other end portion of the lever 240 is provided with a coupling portion 243. The connection portion 243 has a connection hole 243a. An actuator described later is connected to the connection portion 243. The bearing hole 242 may be, for example, a long hole that is longer in a direction perpendicular to the rotation axis direction and the axial direction of the lever 240 (the left-right direction in fig. 5 described later) than in the axial direction of the lever 240.

A large diameter portion 244 is formed between the flat portion 241 and the connecting portion 243 in the lever portion 240. The outer diameter of the rod large-diameter portion 244 is larger than the portion of the rod 240 that is continuous with the flat portion 241 side and the connecting portion 243 side with respect to the rod large-diameter portion 244.

The first case member 110 is formed with an insertion hole 113. One end 113a of the insertion hole 113 is opened outside the first case member 110. The insertion hole 113 extends in a plane direction perpendicular to the rotation axis direction, for example. The insertion hole 113 is located radially outward of the through hole 111 (the intake passage 130). The insertion hole 113 is inserted through the flat portion 241 side of the lever 240. The lever portion large diameter portion 244 is guided by the inner wall surface of the insertion hole 113 of the first housing member 110. Therefore, the movement of the insertion hole 113 other than the center axial direction (the center axial direction of the lever 240) is restricted in the lever 240.

The first case member 110 has a housing hole 114. The receiving hole 114 is formed in the wall surface 112c of the receiving groove 112 b. The receiving hole 114 is recessed from the wall surface 112c toward the intake port 10 (toward the side away from the second case member 120). The accommodation hole 114 has a substantially circular arc shape when viewed from the rotation axis direction. The accommodation hole 114 extends in the wall surface 112c in the rotational direction with respect to the coupling member 230. The accommodating hole 114 is spaced apart from the bearing holes 231, 232 in the rotation axis direction. The housing hole 114 is located closer to the second case member 120 (the first throttle member 210) than the insertion hole 113.

A communication hole 115 is formed in the first case member 110. The communication hole 115 communicates the insertion hole 113 with the accommodation hole 114. The communication hole 115 is formed in a substantially middle portion of the accommodation hole 114 in the rotation direction. The communication hole 115 extends substantially parallel to the extending direction of the insertion hole 113. The width of the through hole 115 in the plane direction perpendicular to the extending direction and the rotation axis direction of the insertion hole 113 is larger than the outer diameter of the rod portion connecting portion 234 of the connecting member 230. The communication hole 115 is a long hole that satisfies the condition that: the width of the insertion hole 113 in the extending direction is larger than the width of the insertion hole 113 in the plane direction perpendicular to the extending direction and the rotation axis direction.

The connecting member 230 is accommodated in the accommodation hole 114. The accommodating hole 114 has a longer length in the rotation direction and a larger width in the radial direction than the connecting member 230. Therefore, the movement of the coupling member 230 in the plane direction perpendicular to the rotation axis direction is allowed in the housing hole 114.

The rod portion connecting portion 234 is inserted into the insertion hole 113 from the communication hole 115. The bearing hole 242 of the rod 240 inserted through the insertion hole 113 is opposed to the communication hole 115. The rod portion connecting portion 234 is inserted into (connected to) the bearing hole 242. The lever portion connecting portion 234 is pivotally supported by the bearing hole 242.

Fig. 4 is a cross-sectional view taken along line IV-IV of fig. 2. As shown by a broken line in fig. 4, the first throttle member 210 has a coupling shaft portion 213 and a rotation shaft portion 214. The coupling shaft portion 213 and the rotation shaft portion 214 protrude in the rotation axis direction from an end surface of the first throttle member 210 on the intake port 10 side (on the wall surface 112c side of the housing groove 112 b). The connecting shaft portion 213 and the rotating shaft portion 214 extend to the depth side of the paper surface in fig. 4. The rotation shaft 214 extends parallel to the coupling shaft 213.

The outer diameter of the coupling shaft 213 is smaller than the inner diameter of the bearing hole 231 of the coupling member 230. The coupling shaft 213 is inserted into the bearing hole 231. The coupling shaft 213 is pivotally supported by the bearing hole 231. The outer diameter of the rotating shaft portion 214 is smaller than the inner diameter of the bearing hole 112d of the first housing member 110. The rotation shaft 214 is inserted into one of the bearing holes 112d. The rotation shaft portion 214 is pivotally supported by the bearing hole 112d (see fig. 2). That is, the rotation shaft portion 214 connects the first throttle member 210 to the wall surface 112c, and the wall surface 112c faces the first throttle member 210 in the rotation axis direction.

The second throttle member 220 has a connecting shaft portion 223 and a rotating shaft portion 224. The coupling shaft portion 223 and the rotation shaft portion 224 protrude in the rotation axis direction from an end surface of the second throttle member 220 on the air inlet 10 side (the wall surface 112c side of the housing groove 112 b). The connecting shaft portion 223 and the rotating shaft portion 224 extend to the deep side of the paper surface in fig. 4. The rotation shaft 224 extends parallel to the connection shaft 223.

The outer diameter of the coupling shaft 223 is smaller than the inner diameter of the bearing hole 232 of the coupling member 230. The coupling shaft 223 is inserted into the bearing hole 232. The coupling shaft 223 is pivotally supported by the bearing hole 232. The outer diameter of the rotating shaft 224 is smaller than the inner diameter of the bearing hole 112d. The rotation shaft 224 is inserted into the other bearing hole 112d. The rotation shaft 224 is pivotally supported by the bearing hole 112d (see fig. 2). That is, the rotation shaft portion 224 connects the second throttle member 220 to the wall surface 112c, and the wall surface 112c faces the second throttle member 220 in the rotation axis direction.

Thus, the link mechanism 200 is constituted by a four-joint link mechanism. The four links (joints) are a first throttle member 210, a second throttle member 220, a first housing member 110, and a connecting member 230. The link mechanism 200 is constituted by a four-joint link mechanism, and thus is limited in interlocking and easy to control in a single degree of freedom.

Fig. 5 is a first diagram for explaining the operation of the link mechanism 200. Fig. 5, 6, and 7 below show views from the suction port 10 side. As shown in fig. 5, one end of the drive spindle 251 of the actuator 250 is coupled to the coupling portion 243 of the lever 240.

In the configuration shown in fig. 5, the first throttle member 210 and the second throttle member 220 abut against each other. At this time, as shown in fig. 2 and 4, the protruding portion 215, which is a radially inner portion of the first throttle member 210, protrudes into the intake passage 130. The protrusion 225, which is a radially inner portion of the second throttle member 220, protrudes into the intake passage 130. The positions of the first throttle member 210 and the second throttle member 220 at this time are referred to as throttle positions.

In the throttle position, the ends 215a, 215b in the rotation direction of the protruding portion 215 are in contact with the ends 225a, 225b in the rotation direction of the protruding portion 225. An annular aperture 260 is formed by the tab 215 and the tab 225. The inner diameter of the annular hole 260 is smaller than the inner diameter of the portion of the suction passage 130 where the protruding portions 215, 225 protrude. The inner diameter of the annular hole 260 is smaller than the inner diameter of any portion of the intake passage 130, for example.

Fig. 6 is a second diagram for explaining the operation of the link mechanism 200. Fig. 7 is a third diagram for explaining the operation of the link mechanism 200. The actuator 250 linearly moves the lever 240 in a direction intersecting the rotation axis direction (up-down direction in fig. 6 and 7). The lever 240 moves upward from the state shown in fig. 5. In the configuration of fig. 7, the amount of movement of the lever 240 relative to the configuration of fig. 5 is greater than in the configuration of fig. 6.

When the lever 240 moves, the coupling member 230 also moves upward as shown in fig. 6 and 7 via the lever connecting portion 234. At this time, the coupling member 230 allows rotation about the lever portion connecting portion 234. In addition, the inner diameter of the bearing hole 242 of the stem 240 has a slight play with respect to the outer diameter of the stem connection 234. Therefore, the movement in the plane direction perpendicular to the rotation axis direction is slightly allowed in the coupling member 230.

As described above, the link mechanism 200 is a four-joint link mechanism, and the connection member 230, the first throttle member 210, and the second throttle member 220 show a state of a single degree of freedom with respect to the first housing member 110. Specifically, the coupling member 230 slightly rotates counterclockwise and slightly swings in the left-right direction within the allowable range as shown in fig. 6 and 7.

In the first throttle member 210, the rotation shaft portion 214 is pivotally supported by the first housing member 110, and thus movement in the plane direction perpendicular to the rotation shaft direction is restricted. The coupling shaft 213 is pivotally supported by the coupling member 230. Since the coupling member 230 is provided so as to be allowed to move, the coupling shaft 213 can move in the plane direction perpendicular to the rotation axis direction. As a result, the first throttle member 210 rotates clockwise as shown in fig. 6 and 7 with the rotation shaft 214 as the rotation center along with the movement of the coupling member 230.

Similarly, in the second throttle member 220, the rotation shaft portion 224 is pivotally supported by the first housing member 110, and thus movement in the plane direction perpendicular to the rotation shaft direction is restricted. The coupling shaft portion 223 is pivotally supported by the coupling member 230. Since the coupling member 230 is provided so as to be allowed to move, the coupling shaft portion 223 can move in the plane direction perpendicular to the rotation axis direction. As a result, the second throttle member 220 rotates clockwise as shown in fig. 6 and 7 with the rotation shaft 224 as the rotation center along with the movement of the coupling member 230.

Thus, the first throttle member 210 and the second throttle member 220 move in the direction of being spaced apart from each other in the order of fig. 6 and 7. The protruding portions 215 and 225 move radially outward (retracted position) with respect to the throttle position. In the retracted position, for example, the protruding portions 215 and 225 are aligned with the inner wall surface of the intake passage 130 or are located radially outward of the inner wall surface of the intake passage 130. When moving from the retracted position to the throttle position, the first throttle member 210 and the second throttle member 220 approach each other and come into contact with each other in the order of fig. 7, 6, and 5. In this way, the first throttle member 210 and the second throttle member 220 are switched between the throttle position and the retracted position according to the rotation angle about the rotation shaft portions 214 and 224.

Fig. 8 is a drawing of the two-dot chain line portion of fig. 2. Although the first throttle member 210 side will be described below as an example, the second throttle member 220 is also configured (arranged) in the same manner as the first throttle member 210. In fig. 8, the first throttle member 210 is in the throttle position. In the throttle position, the protruding portion 215 of the first throttle member 210 and the protruding portion 225 of the second throttle member 220 protrude radially inward most in the intake passage 130.

The protruding portion 215 of the first throttle member 210 has an opposing surface 215c. The facing surface 215c faces the leading edge LE of the vane 9d of the compressor wheel 9. The leading edge LE is the upstream end of the flow direction of the air in the blade 9 d. Here, the leading edge LE is inclined with respect to the radial direction. The leading edge LE is located on the left side (the side away from the intake port 10, the bearing 6 side) as viewed in fig. 8 as approaching the radially outer side. The leading edge LE may be parallel with respect to the radial direction.

The outer peripheral end 9e of the leading edge LE is the most radially outward portion of the leading edge LE. Here, the outer peripheral end 9e is most toward the left side (the side away from the intake port 10, the bearing 6 side) as viewed in fig. 8 in the leading edge LE.

The inner peripheral end 9f of the leading edge LE is the most radially inward portion of the leading edge LE. Here, the inner peripheral end 9f is most on the right side (the suction port 10 side, the side away from the bearing 6) as viewed in fig. 8 in the leading edge LE.

The outer peripheral end 9e is positioned axially to the left as viewed in fig. 8 than the opposing surface 215c of the projection 215. The inner peripheral end 9f is positioned axially to the right in fig. 8 than the opposing surface 215c of the protruding portion 215. That is, the facing surface 215c is provided between the axial position of the outer peripheral end 9e of the leading edge LE and the axial position of the inner peripheral end 9f of the leading edge LE. Thus, even when the leading edge LE is inclined with respect to the direction perpendicular to the axial direction, the outer peripheral end 9e can be brought close to the protruding portion 215.

As shown in fig. 8, a distance (shortest distance, axial distance) between the facing surface 215c of the protruding portion 215 of the first throttle member 210 and the outer peripheral end 9e of the leading edge LE is set to be a distance LL. Further, the maximum protruding height (height at the throttle position) of the protruding portion 215 protruding from the inner wall surface of the intake passage 130 is set to a height h _max.

Fig. 9 is a graph showing a relationship between the distance LL and the improvement rate of the heat insulation efficiency. In fig. 9, the vertical axis represents the distance LL described above. The horizontal axis represents the improvement rate of the heat insulation efficiency. Here, the improvement rate of the heat insulating efficiency indicates a rate of improving the heat insulating efficiency (rising) by moving the first throttle member 210 and the second throttle member 220 to the throttle position with respect to the heat insulating efficiency at the fully open position. In the fully open position, the protruding portion 215 of the first throttle member 210 and the protruding portion 225 of the second throttle member 220 are positioned furthest radially outward (e.g., radially outward of the intake passage 130).

In fig. 9, the legends AA, AB, and AC indicate that the compression ratios of air are different from each other. The compression ratio of legend AA is lowest and the compression ratio of legend AC is highest. As shown in fig. 9, the smaller the distance LL is, the higher the improvement rate of the heat insulation efficiency is at each compression ratio. That is, the rate of improvement of the heat insulation efficiency increases as the first throttle member 210 approaches the leading edge LE.

Fig. 10 is a view for explaining the range of arrangement of the protruding portion 215 of the first throttle member 210. Fig. 10 shows a diagram turned upside down and left and right with respect to fig. 8 for easy understanding of the correspondence relation with fig. 11. The air throttled by the protruding portion 215 and separated from the inner wall surface of the intake passage 130 gradually expands radially outward as indicated by an arrow FL in fig. 10 and flows in the rotation axis direction. It is known that, in this case, the following relationship of equation 1 is established in the flow of the peeled air. Here, the distance X represents a distance between the facing surface 215c of the protruding portion 215 and a position where the peeled air reattaches to the inner wall surface of the intake passage 130. Re represents the Reynolds number.

[ 1]

Fig. 11 is a graph showing the result of simulation of the flow of the peeled air based on the equation 1. In fig. 11, the horizontal axis represents a ratio (hereinafter referred to as an x ratio) calculated by dividing the distance x toward the downstream side by the height h _max of the protruding portion 215, with the facing surface 215c being 0. The vertical axis represents a ratio calculated by dividing the distance r from the inner wall surface of the intake passage 130 toward the radial inner side by the height h _max of the protruding portion 215.

Legends BA, BB, BC differ from each other in the flow rate of air. The flow rate of legend BA is highest and the flow rate of legend BC is lowest. As shown in fig. 11, when the x ratio exceeds 4 at each flow rate, the air rapidly expands radially outward and flows. Conversely, in the range where the x ratio is 4 or less, the air spreads radially outward only in the range of 10% or less of the height h _max of the protruding portion 215.

Therefore, in the link mechanism 200, as shown in fig. 10, the first throttle member 210 is disposed at a position such that the distance LL between the facing surface 215c of the protruding portion 215 of the first throttle member 210 and the outer peripheral end 9e of the leading edge LE is 4 times or less the height h _max of the protruding portion 215. That is, the leading edge LE is located in a range where the x ratio is 4 or less with respect to the opposing surface 215c of the protruding portion 215.

As a result, the air passing through the protruding portion 215 reaches the leading edge LE while hardly expanding radially outward. That is, the compressor wheel 9 can compress the air while the throttling effect obtained by the first throttling member 210 is sufficiently retained. In addition, since the protruding portion 215 and the leading edge LE have the above-described positional relationship, the flow velocity from the inner side in the radial direction of the leading edge LE to the vicinity of the intermediate position is increased and the inflow angle is made good. This makes it possible to supplement the work of the compressor wheel 9 that cannot be obtained in the vicinity of the shroud 121a with the work from the inner side in the radial direction of the leading edge LE to the vicinity of the intermediate position.

An embodiment of the present disclosure has been described above with reference to the drawings, but the present disclosure is of course not limited to this embodiment. Various modifications and corrections can be conceived by those skilled in the art within the scope of the claims, and these modifications and corrections are, of course, also within the technical scope of the present disclosure.

For example, in the above embodiment, the case where the first throttle member 210 and the second throttle member 220 are included as the throttle member is described. However, at least one of the first throttle member 210 and the second throttle member 220 may be provided. In addition, three or more throttle members may be provided.

The link mechanism 200 described in the above embodiment is only one example of a throttle mechanism. The throttle mechanism may be any mechanism as long as it can change the radial position of the throttle member and move the throttle member to the throttle position and the retracted position (fully open position).

In the above embodiment, the facing surface 215c is provided between the position in the axial direction of the outer peripheral end 9e of the leading edge LE and the position in the axial direction of the inner peripheral end 9f of the leading edge LE. In other words, the outer peripheral end 9e and the inner peripheral end 9f are located on axially opposite sides with respect to the facing surface 215 c. However, the inner peripheral end 9f may be located on a radial extension of the opposing surface 215 c. The inner peripheral end 9f may be located closer to the outer peripheral end 9e than the opposing surface 215 c.

Industrial applicability

The present disclosure is applicable to centrifugal compressors and superchargers.

Symbol description

9: Compressor wheels (impellers); 9a: a main body portion; 9b: an outer peripheral surface; 9d: a blade; 9e: a peripheral end; 9f: an inner peripheral end; 130: an air intake passage; 200: a link mechanism (throttle mechanism); 210: a first throttle member (throttle member); 215c: an opposing face; 220: a second throttle member (throttle member); c: a centrifugal compressor; LE: a leading edge; LL: a distance; TC: a supercharger.

Claims (3)

1. A centrifugal compressor is characterized by comprising:

an impeller having a main body and a plurality of blades provided on an outer peripheral surface of the main body;

an intake passage facing the impeller in a rotation axis direction;

and a throttle mechanism that has a throttle member provided in the intake passage, and that is capable of moving in a radial direction of the impeller and that is switchable between a throttle position protruding into the intake passage and a retracted position located further outward in the radial direction than the throttle position, wherein a ratio calculated by dividing a distance between an outer peripheral end of a leading edge of the vane and the throttle member by a maximum protruding height of the throttle member from an inner wall surface of the intake passage is 4 or less.

2. The centrifugal compressor according to claim 1, wherein,

The throttle member has an opposing surface opposing the outer peripheral end in the axial direction of the impeller,

The opposed surface is disposed between the axial position of the outer peripheral end and the axial position of the inner peripheral end of the leading edge.

3. A supercharger is characterized in that,

The centrifugal compressor according to claim 1 or 2.